Alcoholic based products are usually preferred for their fast drying and excellent solubilizing properties. However, inorganic salts are generally insoluble in alcohol so formulations require higher water to alcohol ratios which make wetter products that dry more slowly. Also salt concentrations are limited by their solubility in such systems. On the other hand the solubility of organic compounds (e.g. perfumes) depend on high alcohol content unless emulsified, so compromises are usually required. Certain salts such as sodium bicarbonate decompose in water or water/alcohol solutions and convert to sodium carbonate, so a powder suspension must be used.
Present novel aqueous alcoholic suspensions containing hydroxyethyl cellulose as the essential suspending agent allows alcohol soluble and insoluble ingredients to be used in fast drying products containing a high alcohol content.
The prior art is replete with compositions containing hydroxyethyl cellulose as a thickening agent per se or in combination with other thickening agents as disclosed in U.S. Pat. No. 4,002,881 which relates to a dentifrice, and in U.S. Pat. No. 4,145,413 which relates to a skin darkening composition. The hydroxyethyl cellulose forms an aqueous gel in aforesaid compositions, thereby effecting a thickening action.
Another group of compositions which utilize hydroxyethyl cellulose as a means of controlling drug release of a medicated tablet, are sustained release therapeutic formulations, as disclosed in U.S. Pat. Nos. 3,136,695, 4,235,870 and 4,167,558.
Hydroxyethyl cellulose has also been used as a stabilizer for a prostaglandin E. group containing formulation as shown in U.S. Pat. No. 4,036,954; and as a film forming carrier for a medicament as shown in U.S. Pat. No. 4,136,162.
Stable aqueous dispersions or suspensions of solids or water insoluble compounds containing hydroxyethyl cellulose as one member of a stabilizing or suspending combination are disclosed in U.S. Pat. No. 3,258,326, which relates to a solid pesticidal agent in aqueous media; and by U.S. Pat. No. 3,927,205 which discloses an aqueous suspension of a water insoluble or sparingly soluble pharmaceutical. U.S. Pat. No. 3,287,222 additionally discloses an aqueous solution or suspension of a therapeutic agent containing hydroxyethyl cellulose as a thickening agent, useful as an impregnant for a synthetic medical dressing.
U.S. Pat. No. 3,290,218 further discloses that an aqueous or non-aqueous suspension of water-insoluble ethyl cellulose produces a stable suspension of a pharmaceutically or cosmetically active solid material. It is essential that said ethyl cellulose be substantially insoluble in the aqueous or non-aqueous carrier liquids.
Aqueous ethanol solutions of sodium or potassium bicarbonate as deodorant products have been disclosed in British Pat. No. 1,553,739. Although said bicarbonate solutions are efficacious deodorants, underarm irritation has been observed at the 10% level of potassium bicarbonate. It has also been found that aqueous or aqueous/alcoholic sodium bicarbonate solutions are pH unstable.
Aging studies have shown that the bicarbonate in solution breaks down liberating CO.sub.2 and gradually converts into sodium carbonate (a known skin irritant). Bicarbonate solutions also have solubility limitations. Proportionately larger amounts of water are required for higher bicarbonate levels. Consequently less alcohol is permitted which results in wetter, slower drying products. Also, the preparation of sodium bicarbonate solutions above 6.9% are impossible due to its limited water solubility.
The prior art also discloses aerosol suspensions, dispensed via a pressurized container, containing sodium bicarbonate slurried with propellants in a 50:50 mixture in U.S. Pat. No. 2,959,225; and alkali metal bicarbonate in a 0.3 to 15% propellant-soluble vehicle such as ethanol with about 90% propellent in British Pat. No. 1,476,117. The difficulties and disadvantages encountered with aerosol suspensions of sodium or potassium bicarbonate discussed in aforesaid patents, include the settling and/or agglomeration of the dry particles, clogging of the dispensing nozzle, non-uniform spray of deodorant material, nonadherence of the bicarbonate deodorant to the sprayed area due to the bounce-off of said dry powder and/or too wet a spray resulting in too long a drying time, in addition to being detrimental to the environment.
Cosmetic sticks containing antiperspirants and/or sodium bicarbonate supended in a solid vehicle of a water-insoluble alcohol, such as cetyl alcohol and a silicone oil, is disclosed in U.S. Pat. No. 4,126,679. The difficulty of using sodium bicarbonate in this stick is due to its decomposition into sodium bicarbonate at relatively low temperatures as clearly shown in this patent.
However, there is no disclosure of a stable suspension of finely divided solids in an aqueous alcoholic media, such as ethanol, containing a high alcohol content and a minimal water content, by using hydroxyethyl cellulose as the essential suspending agent. The sodium or potassium bicarbonate pituitous suspension in said high alcoholic low water content media containing hydroxyethyl cellulose suspending agent substantially differs from the prior art aqueous or aqueous alcoholic solutions, aerosol suspensions and solid stick suspensions.